Measuring apparatus system and method

ABSTRACT

Disclosed are a method, device and system for determining a flow rate of an excretion stream within an excretion collection assembly. According to some embodiments of the present invention, one of the constituent elements of the collection assembly includes a sensing module which includes an electrical and/or electromechanical component.

PRIORITY AND CONTINUITY CLAIMS

The present Application is a continuation of U.S. patent applicationSer. No. 15/666,613, filed by the inventor of the present invention,titled “Measuring Apparatus System and Method”, filed on Aug. 2, 2017,which in turn is a continuation of U.S. patent application Ser. No.12/490,414, filed by the inventor of the present invention, titled“Measuring Apparatus System and Method”, filed on Jun. 24, 2009, andwhich in turn claims priority from U.S. Provisional Patent ApplicationNo. 61/075,029, filed on Jun. 24, 2008. Each of the aforementionedapplications are hereby incorporated herein by reference in theirentirety.

FIELD OF THE INVENTION

The present invention relates generally to the field of healthcare. Morespecifically, the present invention relates to systems, apparatuses,mechanisms, circuits and methods which may be used to determine urinedischarge rate and volume of a patient.

BACKGROUND

Note: The terms “Foley catheter”, “bladder catheter”, “urinary catheter”or simply “catheter” are used interchangeably throughout this document.

For simplicity of the description, the present invention will mainly beexplained in connection with urine flow measurement. The same or similarideas, apparatuses, techniques, circuits and methods can be used oradopted for the measurement of other fluids in general and other bodyfluids in particular such as blood or intravenous solution.

In many cases during patient treatment it is necessary to collect anddetermine continuously the accurate amount of discharged urine from thepatient's body. This is routinely done for patients during operations,post-operative patients, patients in intensive care units (ICU), as wellas those with urologic disorders where, for example, urine output isdirectly related to renal function. This type of procedure forcollecting, measuring and monitoring urine takes on extreme importancebecause, for example, sudden changes in urine flow, which can occur atany time, can indicate that there is a deteriorating clinical conditionin the patient. Changes in urine output have been correlated withchanges in cardiac output. The invasive collection of urine andmeasurement of urine output are typically accomplished by firstcatheterizing the patient, i.e. a catheter is passed through the urethraof the patient into the bladder. The other end of the catheter isconnected to a container or drainage bag through a length of flexibletubing. Typically the bag is supported below the patient from thepatient's bed or other support system such as a wheelchair, and urinedrains by gravity force from the patient through the flexible tubing andinto the collection bag (FIG. 1). In addition to monitoring urine outputas a function of time, the reservoir of a collection bag fills tocapacity at unpredicted intervals and someone must empty or replace thebag so it can fill once again with urine. Patients can sometimesobstruct the flow of urine into the bag by lying on the drain tube.Further, if there is blood in the urine, blood clots can form that mayclog the catheter. In these cases, no urine appears in the bag after anexpected time period. Both a filled bag and blocked tube can cause urinebackup and a backup could cause deleterious effect on the patient'scondition. For all the above and other reasons, monitoring collectionbags and accurately and reliably measuring the urine flow is animportant part of providing effective patient therapy.

In order to measure the patient's urine discharge, the urine drainagebag typically has measurement graduation marking on the bag's wall. Oncein a predetermined amount of time (e.g. one hour), the nurse or doctorvisually checks the urine level in the bag according to the marking andrecords it in a table in the patient's file. When a more accurate urineflow measurement is required, the measurement is done using a measuringdevice (FIG. 2). The device is placed in between the catheter andflexible tubing that leads the urine from the bladder, and the urinarydrainage bag (FIG. 3). One such device (FIG. 2) is a container that hasa volume of about 100-300 ml, and is made of transparent material withgraduated markings (21) along its height. The container has an inlet onthe top that connects to the tubing (24) carrying the urine from thebladder catheter and an outlet (26) with a valve (27) on the bottom ofthe container connected to the drainage bag. Initially, the valve at thebottom of the container is placed in the closed position and all theurine that flows from the bladder is being collected in the container.Other designs of such a measuring device are connected in other ways tothe drainage bag, for example, with a tube connected from the top of thecontainer to the drainage bag. An example of such a device is describedin U.S. Pat. No. 3,345,980. Once in a predetermined time interval (e.g.one hour), the nurse or doctor checks the amount of urine that wascollected during that period of time according to the urine liquid levelin the container and records it in a table in the patient's file. Afterthe urine volume is read, they then pour the urine accumulated in thecontainer to the drainage bag, either by opening the valve on the bottomof the container or by tilting the container and letting the urine flowthrough the tubing that connects to the drainage bag or in any other waydepending on the type of measuring device used. After emptying themeasuring container, it is ready for a new measuring cycle of thepredetermined amount of time.

SUMMARY OF THE INVENTION

The present invention is a measuring apparatus system and method formeasuring body fluid flow rate in general and excretion stream, such asurine flow rate in particular. According to some embodiments of thepresent invention, there may be an excretion collection assembly thatmay include a bag, a tube, a catheter, and a measurement probe which mayalso be referred to as a “measurement unit” or as a “measuring device”.According to some other embodiments of the present invention, there maybe an excretion collection assembly that may include a bag, a tube, anda catheter. According to some embodiments of the present invention,there may be a sensing module for sensing the fluid flow. According tosome embodiments of the present invention, the sensing module mayinclude at least one electrical component and/or at least oneelectromechanical component. According to some embodiments of thepresent invention, at least a portion of the sensing module may beintegral with a bag of the assembly. According to some embodiments ofthe present invention, at least a portion of the sensing module may beintegral with a catheter of the assembly. According to some embodimentsof the present invention, at least a portion of the sensing module maybe integral with a tube of the assembly. According to some embodimentsof the present invention, at least a portion of the sensing module maybe integral with a measurement probe of the assembly. According to someembodiments of the present invention the sensing module may include anonvolatile memory (NVM). According to some embodiments of the presentinvention, the nonvolatile memory may store calibration information.According to some embodiments of the present invention the sensingmodule may include a random access memory (RAM). According to someembodiments of the present invention, the random access memory may storeflow measurement data. According to some embodiments of the presentinvention, the sensing module may include a passive electrical elementsuch as a coil, piezoelectric crystal, motor, solenoid, capacitor,resistor, light emitting diode (LED), laser diode, thermocouple, bimetaland/or a switch. According to some embodiments of the present inventionthe electrical component that may be included in the sensing module maybe an integrated circuit (IC). According to some embodiments of thepresent invention, the electrical component and/or electromechanicalcomponent that may be included in the sensing module may be powered byat least one battery. According to some embodiments of the presentinvention, the electrical component and/or electromechanical componentthat may be included in the sensing module may be powered by at leastone rechargeable battery. According to some embodiments of the presentinvention, the electrical component and/or electromechanical componentthat may be included in the sensing module may be powered by a chemicalreaction associated with the excretion. According to some embodiments ofthe present invention the electrical component and/or electromechanicalcomponent that may be included in the sensing module may receive powerthrough an electrical wire that may be connected to an electrical powersource. According to some embodiments of the present invention, theelectrical component and/or electromechanical component that may beincluded in the sensing module may be adapted to transmit a signalindicative of excretion flow to an external device. According to someembodiments of the present invention, the electrical component and/orelectromechanical component that may be included in the sensing modulemay be adapted to transmit a signal indicative of excretion flow throughan electrical wire to an external device. According to some embodimentsof the present invention, the wire may include a connector which mayinclude a non-volatile memory. According to some embodiments of thepresent invention, the electrical component and/or electromechanicalcomponent that may be included in the sensing module may be adapted totransmit a signal indicative of excretion flow to an external device,wirelessly. According to some embodiments of the present invention, thesystem of the present invention may be discrete. According to someembodiments of the present invention, the system of the presentinvention may include a calibration parameter. According to someembodiments of the present invention, the calibration parameter mayreflect at least one characteristic of the electrical component and/orelectromechanical component that may be included in the sensing module.According to some embodiments of the present invention, the calibrationparameter may be adjusted during production or sorting of the electricalcomponent and/or electromechanical component. According to someembodiments of the present invention, the calibration parameter may beadjusted during production or sorting of the sensing module.

In hospital settings (e.g. ICU and operation room settings) wherepatients may be attached to urinary catheters for monitoring urinevolume, the conventional measuring device's readings may be manuallylogged in a tabular format. This method of urine flow measurement may beinaccurate and may not provide real-time information.

The inaccuracy may be a result of several parameters:

-   -   1. The reading may only be as accurate as the resolution of the        graduating on the measuring container wall.    -   2. The reading may need to be done in precise time intervals,        but in practice the time can vary, and in some cases even up to        50%.    -   3. The reading intervals may typically be once an hour, this        time interval does not let for a continuous flow measurement.    -   4. The urine discharge from the bladder may have a burst flow        nature, this means that the reading accuracy may be limited to        the amount of urine in a burst.    -   5. Urine flowing from the bladder while the measuring container        is being drained into the collecting bag may not be measured.    -   6. Usually the nurse does not lift the tubing in order to drain        all the residual urine that may be in the tube to the measuring        device before reading the urine quantity. This causes a        situation in which the periodical measurements may be performed        while in the tubing there may be each time a different amount of        residual urine and not in an identical condition in which the        tubing may always be empty.    -   7. If the measuring container is not leveled, the tilt may cause        an inaccurate reading.    -   8. If the measuring container fills to its maximum capacity        before being emptied, the collected urine may overflow and may        not be measured.

Other disadvantages of the current measuring method may be:

-   -   1. Since the measuring device may need to be lower than the        patient for the urine to flow by gravity force, it may usually        be attached to the bedside at a low place or under the bed. This        may make the reading of the urine level not comfortable for the        hospital personnel as they may need to bend over in order to        accurately see the urine level.    -   2. At night time when the room is darkened, it may be difficult        to read the measurement unless light is turned on which may        disturb the patient and his roommates.    -   3. The measurement may require human intervention and may        consume precious time of a nurse who may usually have urgent        tasks to deal with.    -   4. There may be a delay from the time urine was excreted from        the bladder until it flows into the measuring container due to        accumulation of urine in the tubing. With children, this delay        can be very significant as the amount of urine discharged may be        significantly less than that of adults.    -   5. When measuring urine discharge from children, the quantity of        urine can be ten times less than that of an adult, therefore the        inaccuracies can be very large. For instance, if an adult        produces 50 ml and the residual urine in the tubing is 5 ml, the        inaccuracy as a result of this factor may be 10%. But if a child        produces 5 ml and the residual urine in the tubing is 5 ml, the        inaccuracy as a result of this factor may be 100%.    -   6. If reading the measuring device is delayed for any reason or        if there is a high amount of urine discharge, the conventional        measuring device may fill to its maximum and overflow, which may        cause the amount that overflowed not to be measured.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a typical setting for measuring urine excretion as currentlyused in hospitals

FIG. 2 is a typical urine measuring device which is currently used inhospitals

FIG. 3 describes the way the currently used measuring device isconnected

FIG. 4, 6 a, 6 b are designs of a tube for accurately measuring theurine flow

FIG. 5 is a design of the measuring device inlet for accuratelymeasuring the urine flow

FIG. 7 is a schematic diagram of different embodiments of the measuringdevice of the present invention

FIG. 8 shows the connection of the measuring device of the presentinvention to a dedicated monitor

FIG. 9 shows the connection of the measuring device of the presentinvention to a vital sign monitor

FIG. 10 shows the connection of several measuring devices of the presentinvention to a central monitor

FIG. 11 shows a data communication setting

FIG. 12 shows data packets transmitted by a transmitter

FIG. 13 shows data packets received by a receiver

FIG. 14, 15 show data packet rate estimation

FIG. 16 shows an example of a capacitive, volume measuring device

FIGS. 17 and 18 are examples of an excretion collection assemblyaccording to the present invention

DETAILED DESCRIPTION

Given the problems described in the Background, there may therefore be aneed for an apparatus that will overcome these problems.

In the following detailed description, numerous specific details are setforth in order to provide a thorough understanding of the invention.However, it will be understood by those skilled in the art that thepresent invention may be practiced without these specific details. Inother instances, well-known methods, procedures, components and circuitshave not been described in detail so as not to obscure the presentinvention. Unless specifically stated otherwise, as apparent from thefollowing discussions, it is appreciated that throughout thespecification discussions utilizing terms such as “processing”,“computing”, “calculating”, “determining”, or the like, refer to theaction and/or processes of a computer or computing system, or similarelectronic computing device, that manipulate and/or transform datarepresented as physical, such as electronic, quantities within thecomputing system's registers and/or memories into other data similarlyrepresented as physical quantities within the computing system'smemories, registers or other such information storage, transmission ordisplay devices. Embodiments of the present invention may includeapparatuses for performing the operations herein. Such apparatus may bespecially constructed for the desired purposes, or it may comprise ageneral-purpose computer selectively activated or reconfigured by acomputer program stored in the computer. Such a computer program may bestored in a computer readable storage medium, such as, but is notlimited to, any type of disk including floppy disks, optical disks,CD-ROMs, DVDs, magnetic-optical disks, read-only memories (ROMs), randomaccess memories (RAMs) electrically programmable read-only memories(EPROMs), electrically erasable and programmable read only memories(EEPROMs), FLASH memories, magnetic or optical cards, or any other typeof media suitable for storing electronic instructions, and capable ofbeing coupled to a computer system bus. The processes and displayspresented herein are not inherently related to any particular computeror other apparatus. Various general-purpose systems may be used withprograms in accordance with the teachings herein, or it may proveconvenient to construct a more specialized apparatus to perform thedesired method. The desired structure for a variety of these systemswill appear from the description below. In addition, embodiments of thepresent invention are not described with reference to any particularprogramming language. It will be appreciated that a variety ofprogramming languages may be used to implement the teachings of theinventions as described herein.

The detailed description set forth below in connection with the drawingsis intended merely as a description of the presently preferredembodiments of the invention, and is not intended to represent the onlyform in which the present invention may be constructed or utilized. Thedescription sets forth the ideas, designs, functions, means, and methodsof implementing the invention in connection with the illustratedembodiments. It is to be understood, however, that the same orequivalent functions and features may be accomplished by differentembodiments that are also intended to be encompassed within the spiritand scope of the invention.

In order to measure urine or liquid flow, a sensing element (sensor) foraccurately sensing the flow rate may be provided. Numerous ways can beused for implementing the sensor, these ways can be grouped into severalfamilies according to their operating principle.

Some embodiments of the present invention may make use of a family ofvariable area type of devices. The operating principle is of having atapered conduit with a variable area along its longitudinal axis, theconduit may have a measuring element in it which can be a ball, a disk,a cone or any other element that obstructs the flow. The measuringelement may be forced towards the narrow end of the conduit by a springor magnet, or electromagnet or gravity or by any other means. The fluidmay flow into the conduit from the narrow end and may come out of theconduit from the wide end. The fluid, as it flows, may push themeasuring element away from the narrow end and towards the wide end ofthe conduit, the amount of movement of the measuring element may beproportional to the flow rate, this movement can be visually orelectrically measured. In some other implementations of a variable areadevice the measuring element may be forced to stay in the same locationin the conduit, the amount of force applied on the measuring element maybe proportional to the fluid flow rate, usually this force may beapplied electrically, by, for example, an electromagnet, and theelectrical current applied may indicate the flow rate.

Other embodiments of the present invention may make use of a family ofdroplet count type of devices. These devices are commonly used inintravenous administration sets. The flowing liquid may be collected ina drip chamber to form droplets, the droplets may then be counted inorder to determine the drop rate and hence the flow rate. There may be avariety of ways in which the droplets may be counted including,optical—in which the drop may obstruct a light beam; capacitive—in whichthe drop may fall between the plates of a two plate capacitor and changethe capacitance of that capacitor; conductive—in which the drop in itsfall may impact on electrical probes and may cause an electricalshort-circuit; pressure—in which the falling drop may impinge on apressure transducer; thermal—in which the drop may impinge on a heatedelement and may cause it to cool. In more advanced droplet counters, thedrop size or volume can also be measured in order to provide a moreaccurate measurement of the flow rate. There may be a variety of waysthe drop volume can be measured, among those are, optical—in which thetime it takes the drop to fall across a light beam may be measured orthe drop image size on an image sensor may be measured; capacitive—inwhich the amount of capacitance change of a two plate capacitor may bemeasured to determine the drop volume falling in between the two plates;pressure—in which the amount of pressure change the impinging fallingdrop on a pressure transducer causes, may be measured to determine thedrop volume; thermal—in which the amount of energy needed to be appliedto a heating element in order to keep it in a constant temperature maybe measured to determine the amount of heat removed by the impingingdrop on that heating element, which may be proportional to the dropvolume; resistive—in which the drop may flow on a resistor or on twoparallel resistors and may create an electrical contact between them,the resistance may determine the drop size.

Other embodiments of the present invention may make use of a family ofrotary piston type devices. The operating principle may be of having apiston rotating within a chamber of known volume as the fluid passesthrough the chamber, the number of piston rotations may be counted todetermine the flow rate.

Other embodiments of the present invention may make use of a family ofpressure type of devices. The operating principle may be of having twopressure sensors along a conduit with some means for constricting theflow within the conduit in a point which may be in between the twopressure sensors, the pressure difference between the two sensors maydetermine the flow rate.

Other embodiments of the present invention may make use of a family ofmagnetic type of devices. The operating principle may be of having amagnetic field applied to a metering conduit which may result in apotential difference proportional to the flow velocity perpendicular tothe flux lines, the magnetic flow meter may require a conducting fluid.

Other embodiments of the present invention may make use of a family oftravel time type of devices. The operating principle may be of having amarker inserted into the fluid flow and the travel time of that markeralong a known length of a conduit may be measured to determine the fluidflow rate. There may be a variety of markers that can be used, amongthem are: heat—a heating element may be placed in one point along theconduit and a temperature sensor may be placed in a second pointdownstream of the heating element, the heating element may receiveelectrical pulses that may create heat markers in the flowing fluid andthe temperature sensor may sense these markers. Other markers mayinclude injecting ions, air bubbles or particles.

Other embodiments of the present invention may make use of a family ofheater type of devices. The operating principle may be of having aresistive heating element placed in the flow, the heating element may beheated by an electrical current and the flow of fluid may tend to coolit. Since there may be a relationship between the temperature and theelectrical resistance of the heating element, the flow rate can bedetermined by one of three ways, the required current for keeping theheating element in a constant temperature may be measured, or thecurrent may be measured while applying a constant voltage on the heatingelement, or the voltage across the heating element may be measured whileapplying a constant current through it.

Other embodiments of the present invention may make use of a family ofultrasonic type of devices. The operating principle may be of having anultrasonic wave that may be transmitted in the direction or opposite thedirection of the fluid stream, the propagation speed of the wave may bea function of the fluid flow rate.

Other embodiments of the present invention may make use of a group offamilies for measuring liquid flow which may be based on measuring thevolume of the liquid as a function of time, the change in volume dividedby the time of that change may determine the flow rate. The fluid maytypically be collected in a container for volume measurement, when thecontainer fills up it may be automatically or manually emptied forsuccessive measurements to take place.

One family of volume measurement devices may be the weight type ofdevices. The container may be continuously weighed to determine thevolume and fill rate.

Other families of volume measurement devices may be the capacitive typeof devices. The container may have a plate capacitor immersed in it fromtop to bottom, the liquid may fill the gap between the plates and achange in the liquid level may change the capacitance which can then bemeasured.

Other families of volume measurement devices may be the resistive typeof devices. The container may have a resistor or pair of resistorsimmersed in it from top to bottom, a change in the liquid level maychange the resistance of the resistor(s) which can then be measured todetermine the liquid level.

Other families of volume measurement devices may be the ultrasonic typeof devices. An ultrasonic transducer may be placed at the bottom or topof the container, the transducer may produce an ultrasonic wave that mayprogress and may hit the fluid surface and may return back to thetransducer, the round trip time may be measured to determine the fluidlevel.

Other families of volume measurement devices may be the electrode typeof devices. The container may have electrodes that extend along theheight of the container. The accumulation of liquid in the container mayperform an electrical contact between the electrodes, the number ofelectrodes that the liquid contacts may determine the liquid volume.

The abovementioned families, is not intended to be a complete list ofthe methods and apparatuses for sensing fluid flow rates, several otherfamilies for sensing fluid flow rates can be used or thought of, and theabove mentioned were brought just as an example. Similarly, there may bemany different implementation ways in each family, and in the placeswhere one or several such ways were mentioned, it was done by way ofexample only and not with the intention of presenting a complete list ofways.

The present invention is not limited to a particular type of sensor andany type of sensor known today or to be devised in the future can beused for implementing the measuring device of the present invention.

According to some embodiments of the present invention, there may be ameasuring device which may determine liquid, such as urine flow rate,and transmit a signal indicative of the flow to an external device.According to some embodiments of the present invention, there may be anexcretion collection assembly that may include a catheter, a tube, ameasuring device, and a bag. According to some embodiments of thepresent invention, the measuring device may be a sensing module, atleast a portion of which may be integral with a bag or a tube or acatheter of the assembly. According to some other embodiments of thepresent invention the measuring device may be a measurement probe. Theterm “measuring device” in the specification of the present inventionmay refer to the sensing module and/or to the measurement probe.

In order to accurately measure the urine flow, the tube that may connectthe bladder catheter to the measuring device may need to be kept fullwith urine at all time so that any amount of urine entering the tube onone end will cause the exact same amount of urine to come out at theother end and be measured. In order to achieve that, the internaldiameter of the tube may need to be small enough so that it may not letair bubbles enter the tube, if air is able to enter the tube the urinethat enters the tube from the catheter may not always cause the exactsame amount of urine to exit at the other end and be accuratelymeasured, or urine can spill out of the tube into the measuring deviceand be mistakenly measured while no urine or less urine enters the tubefrom the catheter. Also, if someone moves or raises the tube, someamount of urine may spill from the tube into the measuring device and bemistakenly measured, while later, urine that will flow from the cathetermay be accumulated in the tube and may not be measured for a while.Therefore, by using a tube with a diameter of less than 8 mm the surfacetension of the urine may not let the urine pour out as well as also notletting air go in. Another possible construction of the tube may be tohave a wide diameter tube with a small diameter end connecting to themeasuring device (FIG. 4), this construction of the tube may have thesame benefits of not letting air in as well as the benefit of greaterresistance to bending which may cause occlusion of the tube and may stopthe flow of the urine.

Other constructions of the tube which may achieve the same effect ofallowing out only the exact amount of liquid going in may include:Having a wide tube that may connect to a narrow inlet in the measuringdevice (FIG. 5) or having a tube with varying diameter (FIG. 6a and FIG.6b ).

The tube can be an integral part of the measuring device where it may beattached to the measuring device during manufacturing, or it can be aseparate part that may be connected to the measuring device by the nurseor doctor. The tube can alternatively or additionally be an integralpart of the catheter where it may be attached to the catheter duringmanufacturing.

When a catheter is inserted into the bladder and/or a new tube isconnected to the bladder catheter and/or to the measuring device it mayfirst need to fill up with urine until the urine reaches the measuringdevice and is measured. This time period can be significant, forexample, a tube with a 10 mm diameter and a 1 meter length contains anamount of 79 ml. If the urine excretion is at a rate of 30 ml/h then itmay take over two and a half hours from the time the tube is connecteduntil measuring may start. In order to minimize the delay from the timethe tube is connected to the catheter and/or to the measuring device, orfrom the time the catheter is inserted to the bladder until the urinemeasuring starts due to the time it takes the tube to fill up withurine, the tube can be filled with some liquid such as water or saline.Filling up the tube with liquid can be done by the nurse or doctorbefore or after connecting the tube, or the tube can be pre-filled, forexample, during manufacturing, and the nurse or doctor may connect analready filled tube to the measuring device and/or the bladder catheter.

According to some embodiments of the present invention, the measuringdevice may contain the urine flow path, the urine flow sensing element,the measuring control electronics circuitry, optional individual devicecalibration data, optional memory for storing the measurements, and theelectronic circuitry for transmitting the measurements, integrated asone system (FIG. 7) that may be packaged together in the same sensingmodule. According to some embodiments of the present invention, theentire, or a portion of the sensing module can be integral with thetube. According to some other embodiments of the present invention, theentire, or a portion of the sensing module can be integral with theurine collection bag. According to some other embodiments of the presentinvention, the entire, or a portion of the sensing module can beintegral with the catheter. According to some other embodiments of thepresent invention, the entire, or a portion of the sensing module can beintegral with a measurement probe connected in between the urinecollection bag and the catheter, whether directly connected orindirectly with some tubing in between.

Since the device of the present invention may include the urine flowpath that may be connected to the tube that may be connected to thecatheter that may be connected to the patient's bladder, the device mayeither be washable and sterilize-able, or disposable.

In the case where the device is disposable, either when it is integratedas part of the urine collection bag, or as part of the tube, or as partof the catheter, or as part of a measurement probe and discarded as partof the discard of the bag or tube or catheter or measurement probe, orif it is a separate disposable device, the system cost may need to bevery low in order to enable it to be practically disposable. This can beachieved by having part or all the electronic circuits and optionallyalso the flow sensing element or part of it and optionally also thecalibration data, and optionally also the measurements memory,integrated into one or more integrated circuit (IC).

The most cost effective solution may be to have part or all theelectronic circuits and part or the entire flow sensing element, andpart or all the calibration data if it exists, and part or all of theoptional measurements memory, integrated into a single integratedcircuit.

By having the entire device integrated into one module, either a fullydisposable or sterilize-able discrete measuring system, it may bepossible to satisfy the objectives of:

-   -   1. Accuracy—By having the whole system integrated in one device        the measurement may be more exact due to the following reasons.        -   There may not be any errors occurring from alignment between            a fixed measuring instrument and a disposable or            sterilize-able device connected to it.        -   There may be greater accuracy because of the great proximity            between the urine and the sensing element, this may not be            achieved with a two element device.        -   The electrical noise level may be very low in a unified            discrete system which may lead to a higher SNR (Signal to            Noise Ratio) and therefore to higher measurement accuracy.        -   A discrete system may enable the construction of much more            sensitive and precise sensors than a two element system.    -   2. Resolution—By having a discrete system greater measuring        resolutions can be achieved due to the ability to design more        accurate sensors.    -   3. Continuous reading—A discrete system can perform measurement        on very small liquid volume and therefore can provide frequent        readings.    -   4. Delay—Due to the small urine volume that may be required for        performing an exact measurement, the time it takes for that        volume to flow past the sensor may be relatively short and        therefore the reading delay may be relatively small.    -   5. No fixed part attached to bed—Since the entire system may be        disposable or sterilize-able, there may be no fixed part.    -   6. No sensitivity to shaking—A sensor that requires very small        amounts of liquid for measuring the flow may not be influenced        by shaking.    -   7. Handling—A system that may be integrated into the existing        equipment (urine bag or tube or catheter or measurement probe)        can be used almost in the same way as it is being used today. No        special new parts or connections involving the urine may be        needed.    -   8. Cleanness—If the system is disposable, there would be no need        to wash, clean and sterilize it before use. The system may be        sterilized during manufacturing in the same way as other        disposable medical devices.

In order to satisfy the objective of enabling easy and comfortablereading at an eye-level height without need for bending over or turninga light on, the display may be a separate unit. The measuring device cancommunicate the measured values to the display via electrical cable oroptical fiber or wirelessly.

The display unit can be a dedicated display for displaying only urineflow (FIG. 8), or it can be a standard vital signs monitor that iscommonly used in hospitals placed near the patient's bed (FIG. 9), or itcan be a centralized monitor, either dedicated for urine or standardvital signs, located in the nurses' station (FIG. 10).

The measuring device may need to be powered by electrical power in orderfor it to operate. According to some embodiments of the presentinvention, the device can be powered by one or more of severalalternatives.

-   -   1. The device may be powered by a battery. If the measuring        device is disposable, the battery can either be disposable and        part of the disposable device, or, the battery can be attached        or inserted to the measuring device before use and detached        after the use before the discard of the measuring device, in        this case the battery can be rechargeable or not rechargeable.        If the measuring device is reusable, the battery may be attached        or inserted to the measuring device before use and detached        after the use before cleaning and sterilizing the measuring        device, in this case the battery can be rechargeable or not        rechargeable.    -   2. The device may be powered by electricity generated from a        chemical reaction with the urine.    -   3. The device may be powered by electricity generated from        light.    -   4. The device may be powered by an electrical cord connected to        it from a power source, the power source may be part of the        display unit or part of a receiving device or a battery or any        other power source.    -   5. The device may be powered by a magnetic field.

The urine flow of interest may be the flow of urine through the uretersand into the bladder, this may determine the rate of urine produced bythe kidneys. The urine flowing out of the bladder through the cathetermay have a somewhat burst nature and may not flow in a steady rate.There may be several reasons for these bursts and unsteady flow rate,there may be a brief peristaltic motion 1 to 4 times per minute thataffects the pressure on the bladder, in addition there may be movementsof the patient that effect the pressure imposed on the bladder, andthere may be movements of the catheter and tubing during patienttreatment, and movement of the bed by the hospital staff and/or thepatient's relatives. All these as well as other reasons may beresponsible for the fact that the instantaneous flow of urine out of thebladder may not be exactly identical to the instantaneous urine flowinto the bladder. On the other hand, since no urine disappears oraccumulates in the bladder, in the long run the average urine flow intothe bladder may be equal to the average urine flow out of the bladder.It may be possible to estimate the urine flow in the ureters into thebladder from measuring the urine flow out of the bladder. There are manyknown ways, algorithms, methods and circuits in the data communicationand telecommunication field for recovering an original signal after itpassed through a transmission line which added noise or jitter andwander to the original signal. The concepts and notions in the datacommunication and telecommunication field will now be briefly explained.One particular case will be discussed as an example. Information datamay be transmitted from a transmitter (43) to a receiver (45) over anetwork (44) (FIG. 11), usually the data may be transmitted in what iscalled packets or cells, in this example these packets or cells are ofequal size, and the packets or cells are transmitted at equal intervalsof time so that after an amount of time (T) past since the last packetor cell was transmitted a new packet or cell will be transmitted in away that the time interval between the start of transmission of eachpacket or cell and the start of transmission of the consecutive packetor cell is (T) (FIG. 12), the rate that the packets or cells aretransmitted is 1/T. The transmitted packets or cells travel through thenetwork and the network may add jitter and/or wander to the packets orcells so that the packets or cells received at the receiver may nolonger be spaced apart from each other by an amount of time (T) (FIG.13). Therefore, the receiver may have a mechanism which may estimate theoriginal time interval (T) from the varying intervals (T1, T2, T3, T4, .. . ) between the received packets and may output the packets or cellsat the estimated intervals (T′). The estimation mechanism may need tocontinuously follow any changes in the time interval (T) so that anyincrease or decrease of (T) on the transmitter side will result in thesame increase or decrease in the rate that the receiver outputs thepackets or cells (FIG. 14 and FIG. 15). An example of such apparatus canbe seen in U.S. Pat. No. 5,396,492.

In an analogous way, the urine flow rate into the bladder may beanalogous to the transmitted packet or cell rate, the bladder and thecatheter and the tube may be analogous to the network, and the receivermay be analogous to the urine measuring device. Therefore, in ananalogous way, the measuring device can estimate the urine flow into thebladder, from observing the urine flow out of the bladder. Thisestimation can be done by mathematical computation in the measuringdevice, the computing circuitry can be integrated in the same integratedcircuit as other circuits of the measuring device or it can be separate,or the rate estimation can be done outside of the measuring device as ina receiving device or in the display unit.

There may be cases when the patient may be transferred from one locationto another like from the ICU to an operation room or to an x-ray or CTexamination. In these cases, if the display unit is not connected to thebed, but for instance, is fixed to the wall, the measuring device mayneed to be disconnected from the display unit and connected to anotherdisplay unit at the second location. When the measuring device isconnected to the second display unit in the second location, all themeasurement data that may have been collected while in the firstlocation may be lost and there may not be any information regarding howmuch urine was excreted during that time as well as the excretion rate.In addition, there may not be any information regarding the amount ofurine excreted while the patient was in transit. Also, when the patientis returned to the first location, all information since he left thatfirst location and until he was returned back to that first location maybe lost. In order not to lose any information collected, and in order tobe able to keep measuring while not being connected to a display unit,there may be according to some embodiments of the present invention anoption to have a memory in the measuring device which may store themeasurements. This optional memory can be integrated in the sameintegrated circuit (IC) with other electronic circuits of the measuringdevice for cost saving. When the measuring device is reconnected to thesecond display unit, the measuring device may transfer the storedmeasurements to the display unit for display or for retrieving pastexcretion information.

The amount of urine excreted may be in the range of less than 5 ml/hr byinfants to over 100 ml/hr for adults. Measuring low flow rates like thismay require very fine mechanics. Manufacturing such small mechanics to ahigh degree of accuracy may be very costly. Therefore, in order for themeasuring device to be accurate, while keeping manufacturing costs low,the device may be calibrated. Typically this calibration may be doneduring manufacturing or sorting, and calibration information may beextracted during the calibration process. In addition, many of the flowsensing techniques described above as well as other techniques, involveanalog circuitry which may need to be calibrated due to variations inthe electrical component values. In addition, in many cases the sensor,which may be for example a resistive or capacitive sensor, may needcalibration. The calibration can be done in the factory for eachmeasuring device. During the calibration process, calibration data maybe collected. According to some embodiments of the present invention thecalibration data may be stored in a non volatile memory (NVM) in thedevice. The NVM can be integrated in the same integrated circuit withother electronic circuits of the measuring device. It should be notedthat the need for calibration may depend on the type and construction ofthe measuring device, the type of sensor used, and is not alwaysrequired.

FIG. 1 presents an example of a conventional ICU setting in which a tube(103) is connected to a catheter (not shown) which is inserted throughthe ureter to the patient's (105) bladder. The tube leads the urine to ameasuring device (101) which collects the urine. The urine quantity inthe measuring device may then periodically (e.g. each hour) be read andrecorded in the patient's file (104) and then emptied into the drainagebag (102). The empty measuring device may then start a new measuringcycle.

FIG. 2 shows an example of a conventional measuring device which iscommonly used in hospitals, for example, in ICUs and operation rooms.This type of measuring device may require the attention of a nurse whicheach hour or some other predefined time interval may read the amount ofurine that accumulated in the device and may then empty it into theurine collecting bag to start a new measuring cycle. The conventionalmeasuring device (28) may be made of a transparent material so that theurine level accumulating in the device can be visualized through thedevice's wall. The device may fill up with urine entering from a tube(24) that may be connected to the top of the device, the urine may fillup the device from the bottom upwards, and the urine quantity can beread by watching the urine level according to the graduated markings(21) that may be on the device's wall. The crosscut of the lower part(23) of the device may be smaller then that of the higher part (22) inorder to have a finer resolution when the urine quantity is small. Afterthe urine quantity is read, the valve (27) may then be opened to emptythe measuring device into the urine drainage bag (34 in FIG. 3)connected to the device's outlet (26). After the device is empty, thevalve (27) may then be closed and a new measuring cycle may start again.In the case that the nurse did not come to read the device on time, orin the case when the urine excretion was abnormally high and theconventional measuring device is filled to the top, any additional urineentering the device may overflow through the bypass channel (25)directly to the urine drainage bag, this may be done in order to preventbackpressure on the bladder.

FIG. 3 describes an example of an excretion collection assembly showinghow the measuring device (28) may be connected in order to measure urineexcretion. The tip (30) of the Foley catheter (32) may be insertedthrough the urethra and into the bladder, then, the balloon (31) may beinflated using sterile water in order to retain the catheter in thebladder. The inlet of the measuring device (28) may be connected to theFoley catheter (32) using tube (24) which may be connected to thecatheter by means of connector (33). The outlet of the measuring devicemay be connected to the drainage bag (34). The drainage bag may havegraduation markings (35) on it so that the amount of urine collected inthe bag can be roughly determined.

When urine enters a tube with a wide diameter of over 10 mm, the urinecan come out of the other end by gravity force and there may not be adirect relation between the flow rate into the tube and the flow comingout of the tube. FIG. 4 shows an example of a design of a tube that mayallow the urine to come out of the tube only at the same rate it entersthe tube. According to this design, tube (24) may connect to the bladdercatheter by means of connector (41), the tube (24) can be of any width.The outlet of the tube (42) may have a width of less then 8 mm, in thisway the urine in the tube can not spill out of the tube because air maynot be able to enter the tube due to the surface tension of the urine.

FIG. 5 shows another way of achieving the goal of not letting air enterthe tube and causing urine to spill out, by having a tube (24) of anywidth that may be connected to the urinary catheter by means ofconnector (41) and may be connected to the measuring device (28) via aninlet (51) of less then 8 mm.

FIGS. 6a and 6b are other designs for achieving the same goal. In thesetwo designs the width of the tube can vary, diameters 61-69 can be ofany and different widths. If the tube is connected to the measuringdevice via a narrow inlet as in 51 then the end of the tube can be wideas in 69, otherwise the end of the tube may be less then 8 mm as in 63.

Going now to FIG. 7, a schematic description of the measuring deviceaccording to some embodiments of the present invention is shown. Theliquid to be measured may enter the measuring device at inlet (72) andmay pass through the liquid path (73) to the outlet of the measuringdevice (71). A sensing element (74) may sense the flow rate. The sensingelement can be of any type, including any one of the types discussedabove or any other type known today or to be devised in the future. Anelectronic circuitry (75) may be connected to the sensing element inorder to produce a signal that may represent or be indicative of theflow. This circuitry may include analog and/or digital components thatmay operate together with the sensing element and/or control the sensingelement. For example, if a rotor meter is used as the sensing element(74), the number of turns of the rotor may need to be counted, this canbe done for example optically, in this case the electronic circuit (75)may include a light emitting element such as an LED, a light detectingelement as a phototransistor, and the associated analog circuitry forsignal conditioning of the phototransistor signal as well as analogcircuitry for adjusting the intensity of the LED. The electroniccircuitry (75) may also include some digital circuits for counting thenumber of turns of the rotor. It should be noted that circuitry (75) maydepend on the type of sensing element (74) used. Since the flow ofliquid may be measured at one point (e.g. outside of the patient'sbody), there may be a need to estimate the flow rate as it was inanother point upstream (e.g. in the ureters), for this purpose there maybe optional circuitry (49) for estimating the flow at the other point.The flow estimation can alternatively be done by a microprocessor ormicrocontroller or DSP (48) that may optionally be in the measuringdevice. The measurements may then be communicated to an externalreceiving device by communication circuitry (78), the communication link(not shown) can be wired, optical, or wireless. The measuring device maybe powered by a power source (77) which can be a battery, a photovoltaiccell, a chemical reaction element, a coil or other mean for receivingelectromagnetic energy, a wire connected to a power source or any otherpowering means. The measuring device's operation may be controlled bycircuitry (76) which may be optional in a simple design of the measuringdevice. The measuring device may optionally include a microprocessor ormicrocontroller or DSP (48) that can perform a variety of tasks likegenerally controlling the measuring device, lighting LED signals,managing the communication protocol, calculating the flow, estimatingthe flow, calculating and adjusting the measurements according tocalibration parameters, calculating compensation for temperature,viscosity, etc., performing linearization for non linear sensors,sending alarms, and general housekeeping tasks of the measuring device.The measuring device may optionally include a random access memory (RAM)(47) that may store the measurements so that they can be transmitted bythe communication circuitry (78) at a later time, or may beretransmitted if the measuring device is connected to another receivingdevice than the one it was initially connected to, or upon request, orfor some other reason. The optional RAM can also serve as the memory forthe optional microprocessor/microcontroller/DSP (48). It can also serveas a memory for the optional flow estimation circuitry (49) if needed orfor any other element in the measuring device that may require randomaccess memory. The measuring device can include one or more optional RAM(47). The measuring device may optionally include one or more nonvolatile memory (NVM) and/or fuses or anti-fuses (46) for storinginformation like calibration data, measurements, device model number,device serial number, configuration data and/or any other informationwhich may require a non volatile memory. The measuring device mayoptionally include one or more read only memory (ROM) or reprogrammablememory like FLASH memory (79) for storing the program code of theoptional microprocessor/microcontroller/DSP (48) and/or for keepinglinearization curves and/or the states of state machines and/or protocolinformation for the communication circuitry and/or for any other purposethat may require such memory.

Going to FIG. 8, two configurations for connecting the measuring deviceto a display unit according to some embodiments of the present inventionare shown. On the figure of FIG. 8 displayed at the left side of thedrawing sheet there may be a measuring device (86) that may receiveurine from a tube (85) and may output it to a collecting bag (87). Themeasuring device may transmit the measurements to a display unit (81)through a wire (83). The measurements may be displayed graphically onthe display. According to some embodiments of the present invention, themeasuring device may transmit a signal indicative of excretion flow toan external device. According to some embodiments of the presentinvention, the signal may be transmitted through an electrical wire. Thefigure of FIG. 8 displayed on the right side of the drawing sheet showsa measuring device (88) that may receive urine from a tube (85) and mayoutput it to a collecting bag (87). The measuring device may transmitthe measurements to a display unit (82) through a wireless transmitter(84). According to some embodiments of the present invention, themeasuring device may transmit a signal indicative of excretion flow toan external device wirelessly. The measurements may be displayednumerically on the display. In this example, the instantaneous flow rateof 42 ml/h and the amount of urine in the bag of 850 ml are displayed.Of course any other information that can be derived from measuring theurine flow can be displayed, as for instance, the amount of excretionduring the last hour.

FIG. 9 shows a standard vital sign monitor (90) that may be connected toseveral probes like an arterial line (91) for measuring blood pressure,a pulse-oximeter (92) for measuring pulse rate and oxygen saturation inthe blood, a urine measuring device (93) for measuring the urineexcretion rate and volume, and ECG (94) for measuring cardio signals.

FIG. 10 shows a central monitor (99) in the nurses' station that may beconnected to several urine measuring devices (95-98). The measuringdevices may be connected to the monitor (99) either directly by a wiredor wireless communication link or by an optical fiber, or through acommunication network, or the measuring device can be connected to areceiving device that may take care of the transmission of themeasurements to the monitor.

FIG. 11 describes a communication setting in which a transmitter (43)may receive a data stream from a communication link (39). Thetransmitter may encapsulate a fixed number of bits from the data streamreceived at the communication link (39) together with optional protocolheaders and/or trailers into a packet. The transmitter may then transmitthe information encapsulated in packets through a data communicationnetwork (44) to a receiver (45). The packets transmitted from thetransmitter (43) may be transmitted at certain time intervals T inbetween each other as shown in FIG. 12. While the packets pass throughthe network (44), each packet may be delayed for a different amount oftime before it reaches the receiver (45). When the packets reach thereceiver, the time intervals between the packets may no longer be thesame intervals as was when the packets were transmitted from thetransmitter. FIG. 13 shows the packets as they may be received by thereceiver with times T1, T2, T3, T4, . . . which can be equal to, orsmaller or larger then T. Going back to FIG. 11, the receiver (45) mayreceive the packets from the communication network (44) and may stripoff the header and/or trailer from the packets, and may transmit thedata stream out to a communication link (40). The data stream going intothe transmitter (43) from the communication link (39) may be at acertain rate which may cause packets to be transmitted from thetransmitter to the network (44) at time intervals T. Since the packetsmay be received at the receiver (45) at time intervals other then T, thedata stream sent to the communication link (40) may be at a rate whichis different from the rate the data stream entered the transmitter (43)from communication link 39. In order to have the data stream coming outof communication link 40 be at the same rate as the data stream goinginto communication link 39, the time interval T in which the packetswere transmitted by the transmitter (43) may need to be estimated by thereceiver (45), this estimation can be done by using the time intervalsbetween the received packets and applying certain algorithms which arebeyond the scope of the present invention, on those time intervals.

Due to variations in physical conditions like temperature, the rate inwhich the data stream enters the transmitter (43) through thecommunication link (39) can vary, this may cause the time interval T inwhich the packets are transmitted by the transmitter (43) into thenetwork (44) to vary. The estimation mechanism in the receiver (45) mayneed to be able to track the changes in the time interval T.

FIG. 14 shows the packets transmitted by the transmitter (36) withvarying time intervals. The network may add jitter and wander to thesetime intervals in a way that the spacing in time between the packets maychange (37). The receiver may receive the packets from the network andmay estimate the original spacing between the packets (38) as it mayhave been transmitted by the transmitter (36).

FIG. 15 is another description of the result of the estimationmechanism. Packets may be transmitted by the transmitter (43) with timeintervals T between the packets which may vary in the course of time(52). The network (44) may add jitter and wander to the time interval T(53). The receiver (45) may estimate the original time interval T′ (54).

FIG. 16 is an example of a way for measuring liquid flow by measuringthe change of liquid quantity in a vessel (55) during a given period oftime. The liquid quantity in the vessel (55) may be determined bymeasuring the height (57) of the liquid in the vessel. The vessel mayhave a two plate capacitor (56) placed in it vertically, the capacitormay be part of an oscillator circuit (59) and it may be connected to theoscillator circuit (59) with wires (58). The capacitance of thecapacitor may be a function of the area of the plates, the distancebetween the plates, and the dielectric between the plates. When liquidaccumulates in the vessel, it may also gradually fill in the gap betweenthe plates and may change the dielectric between the two plates (56).The change in dielectric may change the capacitance of the capacitor.Since the capacitor may be part of an oscillator circuit (59), a changein the capacitance of the capacitor (56) may cause a similar orcorrelated change in the frequency of the oscillator, therefore,measuring the oscillator's frequency may indicate the liquid level (57)in the vessel. Multiplying the liquid level by (pi*r2) where ‘pi’ is3.14 and ‘r’ is the vessel's radius may provide the quantity of theliquid. The oscillator (59) may be connected to a counter (60) which maycount the number of oscillations of the oscillator. A timer (80) maylatch the count of the counter (60) each second (or once in any otherfixed amount of time) in a register (70) and at the same time may resetthe counter (60). The captured number in the register (70) may be (ormay be proportional to) the frequency of the oscillator (59). Bysubtracting the liquid quantity measured in the previous second (orother fixed amount of time) from the liquid quantity currently measured,the liquid flow may be determined.

FIG. 17 shows an example of an excretion collection assembly accordingto some embodiments of the present invention. One end of a tube (174)may be connected to a catheter (171) through the catheter's connector(173), and the other end of the tube may be connected to a bag (175). Asensing module (172) or a portion of the sensing module may be integralwith the catheter (171). The sensing module may transmit a signalindicative of the excretion flow and/or receive power through a wire(176). The wire (176) may include a connector (177) which may include anon volatile memory and/or other electrical components.

FIG. 18 shows another example of an excretion collection assemblyaccording to some embodiments of the present invention. One end of atube (174) may be connected to a catheter (171) through the catheter'sconnector (173), and the other end of the tube may be connected to a bag(175). A sensing module (172) or a portion of the sensing module may beintegral with the catheter (171). The sensing module may transmit asignal indicative of the excretion flow wirelessly.

It will now be explained how the present invention may be implementedwith the different embodiments, arrangements, and configurations. Thedifferent embodiments can be implemented with variations, modifications,alternatives, and alterations. These variations, modifications,alternatives, and alterations of the various embodiments, arrangements,and configurations may be used alone or in combination with one anotheras will become more readily apparent to those with skill in the art.

Measuring a low rate flow of body liquids like urine or blood, whereinthe measuring device (sensing module) may have to keep a high level ofsterility while being very accurate and with very fine resolution, aswell as being able to operate in the tough conditions of operating roomsand ICUs may require a very innovative design of the measuring device.

FIG. 3 shows an example of an excretion collection assembly that mayinclude a catheter (32), a tube (24), a measuring device or measurementprobe (28), and a bag (34).

According to some preferred embodiments of the present invention, theremay be a system for determining a flow rate of an excretion streamwithin an excretion collection assembly, that may include a sensingmodule at least a portion of which is integral with a constituentelement of the collection assembly, wherein said sensing module mayinclude at least one electrical component and/or at least oneelectromechanical component.

According to some embodiments of the present invention, the excretioncollection assembly may include a catheter, a tube, and a bag.

According to some embodiments of the present invention, at least aportion of the sensing module may be integral with a tube of theassembly.

According to some embodiments of the present invention, at least aportion of the sensing module may be integral with a bag of theassembly.

According to some embodiments of the present invention, at least aportion of the sensing module may be integral with a catheter of theassembly.

According to some embodiments of the present invention, the excretioncollection assembly may include a catheter, a measurement probe, a tube,and a bag.

According to some embodiments of the present invention, at least aportion of the sensing module may be integral with a measurement probeof the assembly.

In another embodiment of the present invention there may be a system fordetermining a flow rate of a liquid stream that may include at least oneelectrical and/or electromechanical component housed together with themedium through which the liquid flows.

In another embodiment of the present invention there may be a system fordetermining a flow rate of a liquid stream that may include at least oneelectrical and/or electromechanical component housed together with thesterile medium through which the liquid flows. In another embodiment ofthe present invention there may be a system for determining a flow rateof a liquid stream that may include at least one electrical and/orelectromechanical component housed together with the medium throughwhich the liquid flows, and which can be sterilized. In anotherembodiment of the present invention there may be a system fordetermining a flow rate of a liquid stream that may include at least oneelectrical and/or electromechanical component housed together with themedium through which the liquid flows, and which said system issterilized. In another embodiment of the present invention there may bea system for determining a flow rate of a liquid stream that may includeat least one electrical and/or electromechanical component housedtogether with the medium through which the liquid flows constructed in away and from components so that it can be sterilized.

The flow measurement can be done in one of many ways already known inthe art or that are yet to be invented. In whatever technique is usedfor measuring the flow, the flow may be sensed by some sensing elementwhich may be part of a circuitry that may determine the flow. As anexample, consider a capacitive technique that may determine the liquidlevel in a vessel according to the change in capacitance of a capacitorthat may be immersed in the vessel (FIG. 16). In this case the capacitor(56) can be part of an oscillator circuit (59), the frequency in whichthe oscillator circuit may oscillate may depend on the capacitor'scapacitance. The circuit can then include a counter (60) that may countthe number of oscillations in a given amount of time, and that count canbe latched in a register (70) after each such amount of time elapsed.The latched count may be proportional to the frequency which may beproportional to the capacitor's capacitance, which in turn may beproportional to the liquid level (57) in the vessel. In anotherembodiment of the present invention the at least one electrical and/orelectromechanical component of the system for determining a flow rate ofa liquid stream may include at least one sensing element for sensing theflow, housed together with the medium through which the liquid flows.The sensing element can be an electrical component as in the capacitivetechnique just mentioned, or it can be a mechanical element combinedwith an electrical component as in, for example, the variable area typeof devices. In another embodiment of the present invention there may bea system for determining a flow rate of a liquid stream that may includeat least one electrical and/or electromechanical component housedtogether with the medium through which the liquid flows and housedtogether with the flow sensing element.

In some implementations of liquid flow measurement, the measuring devicemay need to be calibrated. Let's look at the example used above of acapacitive sensor. In this example, there can be many variances in theelements that determine the flow, for instance, in the capacitor'scapacitance, in the electronic circuitry component values, in thevessel's diameter, etc. All these variations may need to be compensatedfor when determining the flow of the measured liquid. During, or aftermanufacturing, a calibration step may take place in which calibrationinformation may be extracted, this calibration information may be usedfor compensating for the variations in the different components' values.According to some embodiments of the present invention, the system fordetermining a flow rate of an excretion stream may include a calibrationparameter. According to some embodiments of the present invention, thecalibration parameter may reflect at least one characteristic of theelectrical circuit and/or electromechanical circuit. According to someembodiments of the present invention, the calibration parameter may beadjusted during production or sorting of the electrical circuit and/orelectromechanical circuit. According to some embodiments of the presentinvention, the calibration parameter may reflect at least onecharacteristic of the electrical component and/or electromechanicalcomponent. According to some embodiments of the present invention, thecalibration parameter may be adjusted during production or sorting ofthe electrical component and/or electromechanical component. Accordingto some embodiments of the present invention, the calibration parametermay be adjusted during production or sorting of the sensing module.According to some embodiments of the present invention, the calibrationparameter may be adjusted during production or sorting of themeasurement probe. According to some embodiments of the presentinvention, the sensing module may include a non volatile memory (NVM).In another embodiment of the present invention the at least oneelectrical and/or electromechanical component of the measuring devicemay include at least one non volatile memory (NVM). This non volatilememory can be used among other things like for storing the device modelor serial number, also for storing the calibration data. It should benoted that the calibration data can be stored in the measuring devicewhether the sensing element and/or the sensing circuitry is part of themeasuring device or not.

In cases where the patient may be moved from one location to another,like from the ICU to an x-ray room and back, and in which during thattime the measuring device may be disconnected from the receiving deviceor displaying device, it may be required that the urine excretion willstill be logged during that time. In another embodiment of the presentinvention the at least one electronic circuit of the measuring devicemay include at least one random access memory (RAM) for storingmeasurements. According to some embodiments of the present invention,the sensing module may include a random access memory (RAM). In someembodiments of the present invention, the same memory or memories may beused for other purposes as for instance, the memory for a calculatinglogic that may calculate the flow, or as the memory of a microprocessorthat might be in the measuring device. In yet another embodiment of thepresent invention, the measurements can be logged in a non volatilememory (NVM). In this embodiment, the NVM can be the same one as forstoring other information such as calibration data, or it can be aseparate one.

The measured flow can be read in one of, or several possible ways. Inone embodiment of the present invention, the measured flow can appear asa voltage on an electrical port on the measuring device, for instance, 0volts may determine that there is no flow and 5 volts may determine themaximum flow in the measuring device's measuring range, and voltages inbetween 0 to 5 volts may represent flows in between 0 to maximum flow.In another embodiment of the present invention, the measured flow canappear as pulses on an electrical port on the measuring device in such away that each pulse may represent an amount of liquid that flowedthrough the measuring device, for instance, each pulse may represent 10micro liters. In another embodiment of the present invention, themeasured flow can appear as short circuit pulses or open circuit pulseson an electrical port on the measuring device in such a way that eachshort circuit or open circuit pulse may represent an amount of liquidthat flowed through the measuring device, for instance, each pulse mayrepresent 10 micro liters. In another embodiment of the presentinvention, the measured flow can appear as a square wave on anelectrical port on the measuring device in such a way that the dutycycle of each cycle may represent an amount of liquid that flowedthrough the measuring device, for instance, 0% duty cycle may determinethat there is no flow and 100% duty cycle may determine the maximum flowin the measuring device's measuring range, and duty cycles in between 0%to 100% may represent flows in between 0 to maximum flow. In anotherembodiment of the present invention, the at least one electronic circuitof the measuring device may include at least one communication circuitthat may transmit the measured information to a receiving device or toany number of receiving devices. The information can be transmitted inany agreed upon way between the measuring device and the receivingdevice, for instance, in packets, in cells, or some other way. It may betransmitted in a proprietary protocol or in some standard protocol, in alocal area network (LAN) connection or wide area network (WAN) or someother way like a short haul modem or long haul modem or a directconnection, in any physical layer like RS-232 or RS-485 or V.35, 10BaseT, 100 BaseT, 802.11 or single mode fiber or multimode fiber or IrDAor Bluetooth or any other standard or non standard way. In anyasynchronous or synchronous way. In any encoding like NRZ, RZ, CDP,Manchester, 4B/5B, 8B/10B or any other way. The measurement can also betransmitted from the measuring device in protocols like TCP/IP, UDP andothers. The measurement can be transmitted in a standard OSI Model wayor otherwise in some proprietary way. According to some embodiments ofthe present invention, the electrical component and/or electromechanicalcomponent within the sensing module may be adapted to transmit a signalindicative of excretion flow to an external device. According to someembodiments of the present invention, the electrical component and/orelectromechanical component within the sensing module may be adapted totransmit a signal indicative of excretion flow to an external devicethrough an electrical wire. According to some embodiments of the presentinvention, the electrical wire may include a connector which may includea non-volatile memory. According to some embodiments of the presentinvention, the electrical component and/or electromechanical componentwithin the sensing module may be adapted to transmit a signal indicativeof excretion flow to an external device wirelessly.

In another embodiment of the present invention there may be a system fordetermining and transmitting a flow rate of a liquid stream that mayinclude at least one electronic circuit housed together with the mediumthrough which the liquid flows.

The measured values according to the present invention can betransmitted to a receiving device which may display them or may transferthem to another device or monitor for display. In another embodiment ofthe present invention, there may be a system for determining a flow rateof a liquid stream which may not include means for displaying themeasured values. In another embodiment of the present invention, theremay be a system for determining a flow rate of a liquid stream which maynot include means for displaying the measured values, and may include atleast one electronic circuit housed together with the medium throughwhich the liquid flows.

The urine flow of interest may be the urine flowing into the bladder.The urine flowing into the measuring device may pass through severalphysical elements like the bladder and tubes, which may distort the flowrate in a way that the long time average of the amount of urine flowinginto the bladder may be close to the amount of urine coming out of thebladder, but the instantaneous flow may differ. The elements that maydistort the flow may include the bladder, the Foley catheter, the tubingand/or the measuring device itself. In order to present the flow ofinterest (the flow into the bladder), it may need to be estimated fromthe measured flow in the measuring device. The flow can be estimated bywell known algorithms such as those that can be adopted from thecommunication world. This estimation can be done in the measuring deviceor in the receiving device or elsewhere. In one embodiment of thepresent invention, these algorithms may be implemented in a CPU or a DSPor a microcontroller, the CPU or DSP or microcontroller can serve forother tasks as well, for instance for controlling the measuring device.In another embodiment of the present invention, these algorithms may beimplemented in a dedicated circuitry that may perform the flowestimation algorithm.

The measuring device may require some circuitry for its operation. Thecircuits may include sensor circuitry, flow estimation circuitry,general control circuitry as for lighting LED signals, communicationcircuitry for sending the measurements to the receiving device, flowcalculation circuitry that may calculate the flow rate according to thesensor measurements and can compensate for temperature and calibrationerrors, etc. In one embodiment of the present invention, the circuitryof the measuring device may be implemented with random logic and/oranalog circuitry, this can be very efficient in terms of cost and powerconsumption.

In another embodiment of the present invention, the at least oneelectronic circuit of the measuring device may include at least onetransistor.

In another embodiment of the present invention, part of the circuitryfunctionality may be done with a microprocessor or a DSP that may beincluded in the measuring device, this may have the advantage offlexibility. In yet another embodiment of the present invention, part ofthe circuitry functionality may be done with a microcontroller that maybe included in the measuring device which may also have the advantage offlexibility and typically may cost less than a microprocessor or a DSPand may consume less power.

In another embodiment of the present invention, the at least oneelectronic circuit of the measuring device may include at least oneFLASH memory that among other things can serve as the program memory fora microprocessor or microcontroller or DSP, it can store tables whichcan be used by a processor or the random logic like linearizationtables, it can store the states of state machines, etc.

In order to save costs and reduce power consumption as well as minimizethe size of the measuring device and make it less sensitive to noiselike RFI. In some embodiments of the present invention part or all ofthe electronic circuitry may be integrated into a single integratedcircuit (IC) or it may be divided among several integrated circuits.According to some embodiments of the present invention, the electricalcomponent of the system for determining a flow rate of an excretionstream may be an integrated circuit (IC).

In order to prevent bacteria from entering the measuring device andgetting into the patient's bladder, the measuring device may need to besterilized. In some embodiments of the present invention, the measuringdevice may be fully disposable and may not be transferred from onepatient to another. In other embodiments of the present invention, themeasuring device can be cleaned and sterilized for reuse.

One of the applications of the system of the present invention may be tomeasure urine excretion flow rate and volume. In some embodiments of thepresent invention, the measuring device may be directly or indirectlyconnected to a urinary catheter at the liquid flow input of themeasuring device. In some embodiments of the present invention, themeasuring device may be directly or indirectly connected to a urinedrainage bag or container at the liquid flow output of the measuringdevice. In other embodiments of the present invention, the measuringdevice may be an integral part of the urine drainage bag or container.In other embodiments of the present invention, the measuring device maybe an integral part of the urinary catheter.

The measuring device may continuously or periodically or upon request oron any change in flow, transmit the measurements to a device or toseveral devices that may receive the measurements and can furtherprocess it and/or display it and/or log it and/or initiate an alarmand/or transmit it to other devices and/or control other devices and/orperform any other action based on the measurements. In some embodimentsof the present invention, the measurement may be transmitted over atleast one communication link to at least one receiving device.

The measuring device can be powered from a single power source or fromseveral power sources. Powering the measuring device from several powersources can be done for several reasons, one reason might be for backup,another reason might be that one power source may be a main power sourcewhich may charge a small rechargeable power source for periods when themain power source may be disconnected as when moving the patient fromone room to another. According to some embodiments of the presentinvention, the electrical component and/or electromechanical componentof the system for determining a flow rate of an excretion stream may bepowered by at least one battery. According to some embodiments of thepresent invention, the electrical component and/or electromechanicalcomponent of the system for determining a flow rate of an excretionstream may be powered by at least one rechargeable battery. According tosome embodiments of the present invention, the electrical componentand/or electromechanical component of the system for determining a flowrate of an excretion stream may be powered by a chemical reactionassociated with the excretion. According to some embodiments of thepresent invention, the electrical component and/or electromechanicalcomponent of the system for determining a flow rate of an excretionstream may receive power through an electrical wire that may beconnected to an electrical power source. In some embodiments of thepresent invention, the measuring device may be powered by at least abattery. In some embodiments of the present invention, at least onebattery may be disposable. In other embodiments of the presentinvention, at least one battery may be rechargeable. In otherembodiments of the present invention, the measuring device may bepowered by at least a chemical reaction with a biofluid as for instanceby placing magnesium and copper probes in contact with the biofluid. Insome embodiments of the present invention, the biofluid may be urine. Inother embodiments of the present invention, the biofluid may be blood.In other embodiments of the present invention, the biofluid may be anintravenous solution. In some embodiments of the present invention, themeasuring device may be powered by at least a wire that may be connectedto it from a power source. In some embodiments of the present invention,the power source may be part of, or housed together with, or locatednext to the receiving device. In other embodiments of the presentinvention, the measuring device may be powered by at least a magneticfield. In other embodiments of the present invention, the measuringdevice may be powered at least by energy of light. In some embodimentsof the present invention, the light may be transferred from a light orlaser source through at least one optical fiber. In other embodiments ofthe present invention, the light or laser source may be part of, orhoused together with, or located next to the receiving device.

The measurements can be transmitted to the receiving device or devicesover any number of communication links of the same or different kinds.In some embodiments of the present invention, at least one communicationlink may be at least one radio link. In other embodiments of the presentinvention, at least one communication link may be at least one infra-redlink. In other embodiments of the present invention, at least onecommunication link may be at least one electrical cord. In otherembodiments of the present invention, at least one communication linkmay be at least one power wire. In other embodiments of the presentinvention, at least one communication link may be at least onefiber-optic link. In other embodiments of the present invention, atleast one optical fiber may also be used for the power light.

In order to be able to meet requirements of simplicity, mobility—forbeing able to transfer the patient from one location to another withoutdisrupting the measurement, immunity to chemicals and water showers,immunity to mechanical hits, ease of use, no alignment problems, and nowearing out. In some embodiments of the present invention, the measuringdevice may not be physically and mechanically connected to any otherdevice that may include any of:

-   a) electronic circuitry-   b) active mechanical element like valves, stirs, pumps, motors, etc.-   c) passive mechanical elements like transducers, strain-gages,    propellers, etc.-   d) electronic element like LEDs, photodiodes, phototransistors,    lasers, resistors, capacitors, inductors, transistors, etc.

According to some embodiments of the present invention, there may be asystem for determining a flow rate of an excretion stream which may bediscrete. According to these embodiments, discrete may mean that thesystem may not need to be mechanically attached to any other device, thesystem may be connected to other devices by an electrical wire and/or byan optical fiber and/or wirelessly.

In many implementations of a measuring device there may be differencesbetween the measurements of one device to another device of the samekind. These differences may be due to variations in value or size ofdifferent components that the measuring device is made of. One cause canbe a difference in the physical size of the mechanical elements includedin the measuring device. For example, a measuring device that uses avessel for collecting the liquid may have a volume of (pi*r2*h) where‘pi’ is 3.14 . . . , ‘r’ is the vessel's radius, and ‘h’ is the vessel'sheight. As an example let's assume a nominal radius of 10 mm and amanufacturing variation of 1 mm, in this case the error in volume may be(102−92)/102 which is a 19% error. Another cause can be variations inthe actual value of the electrical components that participate in thesensing circuit. Another cause can be alignment accuracy of themanufacturing process. Each of these as well as other factors maycontribute to the inaccuracy of the measurement. In order to haveaccurate measurements, the measuring device can be calibrated andcalibration information can be stored in the measuring device. In someembodiments of the present invention, the measuring device may includemeans for storing calibration data. In some embodiments of the presentinvention, the calibration data may be stored at least, in at least onenon volatile memory. In other embodiments of the present invention, thecalibration data may be stored by burning fuses or anti-fuses. In otherembodiments of the present invention, the calibration data may be lasertrimmed. In other embodiments of the present invention, the calibrationmay be mechanically adjusted.

The measuring device may be able to operate independently and may notneed to be connected to a display or a receiving device while measuringthe flow of a liquid that flows through it. Once in a while or atrequest, the measuring device can be connected via a communication link,which can be wired or wireless, to a receiving device or a display fordisplaying and/or storing and/or transmitting the measurements. Theremay be a need to display the history of excretion also in cases when themeasuring device is connected to a receiving device or a display but thepatient may be moved to another room for some reason, like for doingx-ray or an operation, and the measuring device may be disconnected fromthe display and may be reconnected to another display in the otherlocation. For these reasons and others there may be a need to log themeasurements in the measuring device. In some embodiments of the presentinvention, the measuring device may include at least one memory forstoring the measurements.

In some applications in which the measuring device may be used, urineexcretion flow rate may be measured. In order to measure the urineexcretion flow, a catheter may be inserted through the urethra and intothe patient's bladder. The other end of the catheter may be connected tothe measuring device which may measure the flow rate of the urineflowing through it. In some embodiments of the present invention, themeasuring device may be connected to the catheter with at least onetube. In order to prevent air from entering the tube or tubes connectingthe catheter to the measuring device, in some embodiments of the presentinvention, the tube or tubes may be of a diameter of less than 8 mm. Inother embodiments of the present invention, the tube or tubes may be ofa varying diameter as depicted as an example in (FIGS. 6a and 6b ). Inyet some other embodiments of the present invention, at least one pointof the at least one tube may have a diameter of less than 8 mm. In otherembodiments of the present invention, the at least one tube may beconnected to at least one outlet which may be of a diameter of less than8 mm (FIG. 5). In other embodiments of the present invention, the atleast one tube may be an integral part of the measuring device. Sincethe tube that may connect the catheter and the measuring device may havea volume which may need to fill up before the measured liquid reachesthe measuring device, the measuring device may not measure any liquidflow until that volume may be filled. For example, using a tube whichhas a volume of 100 ml for measuring urine flow at a rate of 50 ml/hourmay take two hours until the tube is filled and the measuring can start.In order to prevent this “dead” time, in some embodiments of the presentinvention, the at least one tube may initially be filled with liquidwhich may not necessarily be the same material as the measured liquid,in this way, any amount of liquid that may enter the tube or tubes atthe inlet, may cause the exact same amount of liquid to come out of theoutlet of the tube or tubes and be measured. In some embodiments of thepresent invention, the liquid in the tube or tubes may be filled by ahospital staff. In other embodiments of the present invention, theliquid in the tube or tubes may be filled before it gets to thehospital. In other embodiments of the present invention, the liquid inthe tube or tubes may be filled in the factory.

On many occasions, the flow of interest may be at one point while themeasurement may be done at another point along the liquid stream, whilein between the two points there can be medium that may affect theinstantaneous flow rate. In these cases there may be a need to estimatethe flow rate at the point of interest from the measurements that may bedone at the point of measure. This estimation can be done in variousways like computation using a microprocessor or microcontroller or DSP,or computation using dedicated hardware or by implementing a digital oranalog filter. In some embodiments of the present invention, the flow ata certain location may be estimated from the measured flow at anotherlocation.

According to some embodiments of the present invention, there may be asystem for determining a flow rate of an excretion stream within anexcretion collection assembly which may include a sensing module atleast a portion of which may be integral with a constituent element ofthe collection assembly, wherein the sensing module may include apassive electrical element such as coil, piezoelectric crystal, motor,solenoid, capacitor, resistor, light emitting diode (LED), laser diode,thermocouple, bimetal and switch. In some embodiments of the presentinvention, the system may be powered by at least a chemical reactionwith urine. In some embodiments of the present invention, the measuredliquid may be urine. In other embodiments of the present invention, thesystem may be powered by at least a chemical reaction with blood. Inother embodiments of the present invention, the measured liquid may beblood. In other embodiments of the present invention, the system may bepowered by at least a chemical reaction with an intravenous solution. Inother embodiments of the present invention, the measured liquid may bean intravenous solution.

In some embodiments of the present invention, there may be a method ofconnecting an electronic urine measuring device to a patient that mayinclude the step of connecting the inlet of the measuring device to aurinary catheter.

In some embodiments of the present invention, there may be a method ofconnecting an electronic urine measuring device to a patient that mayinclude the steps of:

-   a) connecting the inlet of the measuring device to a tube-   b) connecting the tube to a urinary catheter.

In some embodiments of the present invention, there may be a method ofconnecting an electronic urine measuring device that may have a tube atits inlet to a patient and that may include the step of connecting thetube to a urinary catheter.

In some embodiments of the present invention, there may be a method thatmay include a step of filling the tube with liquid.

In some embodiments of the present invention, there may be a method thatmay include a step of connecting the measuring device to a receivingdevice.

In some embodiments of the present invention, there may be a method thatmay include a step of connecting the measuring device to power.

It should be understood that all of the features and all of theobjectives described in the specification are exemplary, any one ofwhich may be altered or completely removed without detracting from thebreadth of the present invention, which breadth can only be determinedin view of claims yet to be allowed.

The invention claimed is:
 1. A system for estimating a rate of urineproduced by kidneys and flowing into a bladder based on measurement ofan excretion stream within an excretion collection assembly including acatheter, said system comprising: communication circuits to receiveurine flow indicative signals produced by one or more measuring devicesfunctionally associated with a catheter and measuring urine flow out ofthe bladder; estimation circuitry to estimate a urine flow from thekidneys into the bladder based on the received urine flow indicativesignals; and wherein said estimation circuitry includes a signal filter.2. The system according to claim 1, wherein said estimation circuitry isintegral with said measuring device.
 3. The system according to claim 1,wherein said estimation circuitry is integral with a display.
 4. Thesystem according to claim 1, wherein said estimation circuitry isintegral with a receiving device.
 5. The system according to claim 1,wherein said estimation circuitry includes a signal filter which is adigital signal filter.
 6. The system according to claim 1, wherein saidestimation circuitry includes a signal filter which is an analog signalfilter.
 7. A method of estimating a rate of urine produced by kidneysand flowing into a bladder based on measurement of an excretion streamwithin an excretion collection assembly including a catheter, saidmethod comprising: receiving urine flow indicative signals produced byone or more measuring devices functionally associated with a catheterand measuring urine flow out of the bladder; estimating a urine flowfrom the kidneys into the bladder based on the received urine flowindicative signals; and wherein said estimation is at least partiallyperformed using a signal filter.
 8. The method according to claim 7,wherein said estimation is performed by circuitry integral with ameasuring device.
 9. The method according to claim 7, wherein saidestimation is performed by circuitry integral with a display.
 10. Themethod according to claim 7, wherein said estimation is performed bycircuitry integral with a receiving device.
 11. The method according toclaim 7, wherein said estimation is performed using a digital signalfilter.
 12. The method according to claim 7, wherein said estimation isperformed using an analog signal filter.